Let's roll up our sleeves and solve this. We have 661 and we're going to multiply it by 152, essentially adding 661 to itself 152 times.
Step 1: 0 + 661 = 661
Step 2: 661 + 661 = 1322
Step 3: 1322 + 661 = 1983
Step 4: 1983 + 661 = 2644
Step 5: 2644 + 661 = 3305
Step 6: 3305 + 661 = 3966
Step 7: 3966 + 661 = 4627
Step 8: 4627 + 661 = 5288
Step 9: 5288 + 661 = 5949
Step 10: 5949 + 661 = 6610
Step 11: 6610 + 661 = 7271
Step 12: 7271 + 661 = 7932
Step 13: 7932 + 661 = 8593
Step 14: 8593 + 661 = 9254
Step 15: 9254 + 661 = 9915
Step 16: 9915 + 661 = 10576
Step 17: 10576 + 661 = 11237
Step 18: 11237 + 661 = 11898
Step 19: 11898 + 661 = 12559
Step 20: 12559 + 661 = 13220
Step 21: 13220 + 661 = 13881
Step 22: 13881 + 661 = 14542
Step 23: 14542 + 661 = 15203
Step 24: 15203 + 661 = 15864
Step 25: 15864 + 661 = 16525
Step 26: 16525 + 661 = 17186
Step 27: 17186 + 661 = 17847
Step 28: 17847 + 661 = 18508
Step 29: 18508 + 661 = 19169
Step 30: 19169 + 661 = 19830
Step 31: 19830 + 661 = 20491
Step 32: 20491 + 661 = 21152
Step 33: 21152 + 661 = 21813
Step 34: 21813 + 661 = 22474
Step 35: 22474 + 661 = 23135
Step 36: 23135 + 661 = 23796
Step 37: 23796 + 661 = 24457
Step 38: 24457 + 661 = 25118
Step 39: 25118 + 661 = 25779
Step 40: 25779 + 661 = 26440
Step 41: 26440 + 661 = 27101
Step 42: 27101 + 661 = 27762
Step 43: 27762 + 661 = 28423
Step 44: 28423 + 661 = 29084
Step 45: 29084 + 661 = 29745
Step 46: 29745 + 661 = 30406
Step 47: 30406 + 661 = 31067
Step 48: 31067 + 661 = 31728
Step 49: 31728 + 661 = 32389
Step 50: 32389 + 661 = 33050
Step 51: 33050 + 661 = 33711
Step 52: 33711 + 661 = 34372
Step 53: 34372 + 661 = 35033
Step 54: 35033 + 661 = 35694
Step 55: 35694 + 661 = 36355
Step 56: 36355 + 661 = 37016
Step 57: 37016 + 661 = 37677
Step 58: 37677 + 661 = 38338
Step 59: 38338 + 661 = 38999
Step 60: 38999 + 661 = 39660
Step 61: 39660 + 661 = 40321
Step 62: 40321 + 661 = 40982
Step 63: 40982 + 661 = 41643
Step 64: 41643 + 661 = 42304
Step 65: 42304 + 661 = 42965
Step 66: 42965 + 661 = 43626
Step 67: 43626 + 661 = 44287
Step 68: 44287 + 661 = 44948
Step 69: 44948 + 661 = 45609
Step 70: 45609 + 661 = 46270
Step 71: 46270 + 661 = 46931
Step 72: 46931 + 661 = 47592
Step 73: 47592 + 661 = 48253
Step 74: 48253 + 661 = 48914
Step 75: 48914 + 661 = 49575
Step 76: 49575 + 661 = 50236
Step 77: 50236 + 661 = 50897
Step 78: 50897 + 661 = 51558
Step 79: 51558 + 661 = 52219
Step 80: 52219 + 661 = 52880
Step 81: 52880 + 661 = 53541
Step 82: 53541 + 661 = 54202
Step 83: 54202 + 661 = 54863
Step 84: 54863 + 661 = 55524
Step 85: 55524 + 661 = 56185
Step 86: 56185 + 661 = 56846
Step 87: 56846 + 661 = 57507
Step 88: 57507 + 661 = 58168
Step 89: 58168 + 661 = 58829
Step 90: 58829 + 661 = 59490
Step 91: 59490 + 661 = 60151
Step 92: 60151 + 661 = 60812
Step 93: 60812 + 661 = 61473
Step 94: 61473 + 661 = 62134
Step 95: 62134 + 661 = 62795
Step 96: 62795 + 661 = 63456
Step 97: 63456 + 661 = 64117
Step 98: 64117 + 661 = 64778
Step 99: 64778 + 661 = 65439
Step 100: 65439 + 661 = 66100
Step 101: 66100 + 661 = 66761
Step 102: 66761 + 661 = 67422
Step 103: 67422 + 661 = 68083
Step 104: 68083 + 661 = 68744
Step 105: 68744 + 661 = 69405
Step 106: 69405 + 661 = 70066
Step 107: 70066 + 661 = 70727
Step 108: 70727 + 661 = 71388
Step 109: 71388 + 661 = 72049
Step 110: 72049 + 661 = 72710
Step 111: 72710 + 661 = 73371
Step 112: 73371 + 661 = 74032
Step 113: 74032 + 661 = 74693
Step 114: 74693 + 661 = 75354
Step 115: 75354 + 661 = 76015
Step 116: 76015 + 661 = 76676
Step 117: 76676 + 661 = 77337
Step 118: 77337 + 661 = 77998
Step 119: 77998 + 661 = 78659
Step 120: 78659 + 661 = 79320
Step 121: 79320 + 661 = 79981
Step 122: 79981 + 661 = 80642
Step 123: 80642 + 661 = 81303
Step 124: 81303 + 661 = 81964
Step 125: 81964 + 661 = 82625
Step 126: 82625 + 661 = 83286
Step 127: 83286 + 661 = 83947
Step 128: 83947 + 661 = 84608
Step 129: 84608 + 661 = 85269
Step 130: 85269 + 661 = 85930
Step 131: 85930 + 661 = 86591
Step 132: 86591 + 661 = 87252
Step 133: 87252 + 661 = 87913
Step 134: 87913 + 661 = 88574
Step 135: 88574 + 661 = 89235
Step 136: 89235 + 661 = 89896
Step 137: 89896 + 661 = 90557
Step 138: 90557 + 661 = 91218
Step 139: 91218 + 661 = 91879
Step 140: 91879 + 661 = 92540
Step 141: 92540 + 661 = 93201
Step 142: 93201 + 661 = 93862
Step 143: 93862 + 661 = 94523
Step 144: 94523 + 661 = 95184
Step 145: 95184 + 661 = 95845
Step 146: 95845 + 661 = 96506
Step 147: 96506 + 661 = 97167
Step 148: 97167 + 661 = 97828
Step 149: 97828 + 661 = 98489
Step 150: 98489 + 661 = 99150
Step 151: 99150 + 661 = 99811
Step 152: 99811 + 661 = 100472

So, 661*152 = 100472